1) Technical Field of the Invention
The present invention relates to an elevator system and, in particular, relates to the elevator system having an elevator cage vertically moving along an elevator shaft.
2) Description of Related Arts
An elevator cage moving along the elevator shaft constructed in a building, in general, communicates with a control board, fixed on the building, through a cable.
Usage of the cable for data communication causes various disadvantages. For example, at least a part of the weight of the cable is loaded on the elevator cage in a lopsided manner. The lopsided load of the cable on the elevator cage varies depending upon the position of the elevator cage. Thus, the cable can swing when the elevator cage moves, which gives an adverse effect to the elevator cage. Also, an extra space is required for receiving the cable.
In order to eliminate the disadvantages, JP 49-26953 (A) proposes the elevator system including a coaxial cable extending along the elevator shaft and an antenna provided with the elevator cage for communicating with the coaxial cable in a non-contact manner. Further, according to the prior art elevator system, the coaxial cable has to be positioned along the elevator shaft. In case where the elevator system is constructed in a tall building having height more than several hundred meters, especially like a skyscraper, the coaxial cable is quite long and heavy. Therefore, the construction and the maintenance require enormous work and cost.
Also, JP 55-2537 (A) discloses another elevator system including a transmitter provided at the elevator cage, or at the uppermost (or lowermost) portion of the elevator shaft. It also discloses a technique for detecting the position of the elevator cage in the elevator shaft in accordance with a phase shift or a delay time between an electromagnetic wave transmitted from the transmitter and the reflection wave reflected at the elevator cage or at the uppermost (or lowermost) portion of the elevator shaft. The description of the prior art indicates use of ultrasonic and electromagnetic waves, such as visible light, ultraviolet, and infrared. However, usage of the ultrasonic waves causes insufficient accuracy for detection, and electromagnetic waves having wavelengths close to that of visible light are susceptible to dust and smoke so that such they can hardly be received in a reliable manner.
The present invention is addressed to those aforementioned problem, the object of the present invention is to provide an elevator system, in which data communication between a first transceiver provided at a fixed portion in an elevator shaft and a second transceiver provided at an elevator cage is made by means of a millimeter wave.
The elevator system according to the first aspect of the present invention comprises: a first portion positioned in an elevator shaft; a second portion positioned in the elevator shaft, vertically moving relative to the first portion; a first transceiver provided at the first portion; and a second transceiver provided at the second portion; wherein data communication is made between the first and second transceivers by means of a millimeter wave. Data communication by means of a millimeter wave can be made between the first and second portions at a high rate and in a reliable manner.
The elevator system according to the second aspect of the present invention comprises: a first portion positioned in an elevator shaft; a second portion positioned in the elevator shaft, vertically moving relative to the first portion; and a transceiver provided at either one of the first and second portions, for transmitting a millimeter wave to the other one of the first and second portions, and for receiving the millimeter wave reflected at the other one of the first and second portions, so as to determine a distance between the first and second portions. Thus, the distance between the first and second portions can be measured in a precise manner so as to assure a safe motion of the elevator cage.
In the elevator equipment according to the present invention, either one of the first and second transceivers transmits the millimeter wave and then receives the millimeter wave reflected at the other one of the first and second portions, so as to determine a distance between the first and second portions. Therefore, data communication by means of a millimeter wave can be made between the first and second portions at a high rate and in a reliable manner. Also, the distance between the first and second portions can be measured in a precise manner so as to assure a safe motion of the elevator cage.
The elevator system according to the third aspect of the present invention comprises: a) a first portion positioned in an elevator shaft; b) a second portion positioned in the elevator shaft, vertically moving relative to the first portion; c) a first transceiver provided at the first portion; and d) a second transceiver provided at the second portion; e) wherein each of the first and second transceivers includes, a carrier wave generator for generating a carrier wave, a modulator for modulating the carrier wave in accordance with communication data, a transmitter for transmitting the carrier wave modulated by the modulator towards other one of the transceiver, a receiver for receiving the carrier wave transmitted by other one of the transceiver, and a demodulator for demodulating the communication data modulated on the carrier wave received by the receiver; and f) wherein either one of the first and second transceivers includes a distance calculator for calculating a distance between the first and second portions in accordance with the reference signal. In the elevator system so constructed, data communication and detection of the distance between the first and second portions can be achieved without using a cable.
The elevator system according to the fourth aspect of the present invention comprises: a) a first portion positioned in an elevator shaft; b) a second portion positioned in the elevator shaft, vertically moving relative to the first portion; c) a first transceiver provided at the first portion; and d) a second transceiver provided at the second portion; e) wherein either one of the first and second transceivers includes, a carrier generator for generating a carrier wave, a transmitter for transmitting the carrier wave towards other one of the transceiver; f) the other one of the first and second transceivers includes, a receiver for receiving the carrier wave transmitted by one of the transceiver, a modulator for modulating the carrier wave in accordance with communication data, and a transmitter for transmitting the carrier wave modulated by the modulator towards other one of the transceiver; and g) wherein one of the first and second transceivers further includes, a receiver for receiving the carrier wave transmitted from the other one of the transceiver, a demodulator for demodulating the communication data modulated on carrier wave received by the receiver, wherein either one of the first and second transceivers includes a distance calculator for calculating a distance between the first and second portions in accordance with the carrier wave. The elevator system so constructed advantageously eliminates the carrier generator for generating the carrier wave in the other transceiver.
The elevator equipment according to the present invention further comprises a speed calculator for calculating a moving speed of the second portion relative to the first portion, based upon the distance therebetween; and a speed controller for controlling the moving speed of the second portion. Thus, the moving speed of the second portion can be controlled in a precise manner based upon the calculated moving speed.
The elevator equipment according to the present invention, further comprises a power source extending along the elevator shaft; and a power inductor provided at the second portion for receiving a power from the power source due to electromagnetic induction in a non-contact manner; wherein the second transceivers is supplied with the power from the power inductor. Thus, a power cable is eliminated, which is otherwise necessary for supplying the power with the second portion.
Further, the elevator equipment according to the present invention, further comprises a brake device for braking a driver of the second portion when the distance between the first and second portions calculated by the distance calculator is less than a predetermined danger distance. To this end, a bump between the first and second portions can be prevented.
Further, the elevator equipment according to the present invention, further comprises a power cutoff for disabling the power source for supplying the power with the power inductor when the distance between the first and second portions calculated by the distance calculator is less than a predetermined danger distance. To this end, a bump between the first and second portions can be prevented.
It should be noted that, in the elevator equipment according to the present invention, the carrier wave is a millimeter wave.
The elevator system according to the fifth aspect of the present invention comprises: a) a fixed portion positioned in an elevator shaft; b) a first movable portion vertically moving in the elevator shaft relative to the fixed portion; c) a second movable portion positioned in the elevator shaft so that the first portion is intervened between the fixed portion and the second portion, the second portion vertically moving relative to the fixed portion and the first movable portion; and d) a first, second, and third transceivers provided at the fixed, first, and second portion, respectively; wherein the first and third transceivers communicates with each other through the second transceiver. To this end, the motions of the first and second portions can be controlled in a independent and safe manner.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the sprit and scope of the invention will become apparent to those skilled in the art from this detailed description.